1. Field of the Invention
The present invention is concerned with the improvement of fillers for use in paints, plastics, rubber, adhesives, mastics, calks and the like by a process called surfation, which is defined as the alteration of a filler surface by physical and chemical means, both of which are used in the practice of this invention.
2. Description of the Prior Art
Fillers reacted with saturated organic acids have been long established for their improved dispersion and therefore improved properties in composites of fillers and polymers. The surfaces of the fillers are changed from highly active inorganic surfaces to those having exposed hydrocarbon chains compatible with polymers of a similar non-polar nature. Unsaturated acids provide wetting and dispersion in both polar and non-polar media, but are readily oxidized by air or otherwise degraded to reduce their stabilities and improved properties.
Prior U.S. patent art reveals many examples of various organic acid treatments of calcite fillers. These patents are: U.S. Pat. Nos. 1,264,092; 1,832,416; 1,832,417; 2,199,710; 2,345,191, and 2,374,741. In addition, certain combination treatments with chlorinated paraffins, rosin, fatty acids and esters have been disclosed in U.S. Pat. No. 2,663,695, the use of oil vapor in U.S. Pat. No. 2,050,193, and sulfur, fatty acids and oils in U.S. Pat. No. 2,199,710. Unsaturated acid salts have been utilized for treating kaolinite in U.S. Pat. No. 3,085,080. Alumina hydrate filler is treated with fatty acids in U.S. Pat. No. 4,283,316.
The prior art does not report that organic acids are reactive with a number of minerals that have basic and amphoteric sites, either completely or partially. Further, a wide range of both mono-and di-basic acids from 3 to 24 carbon atoms provide exceptional improvements and are susceptible to the same degradation both in preparation and use. Neither the equivalence of the lower and higher members of the unsaturated acids not their instabilities has been reported in the prior art. In addition, it has been discovered that a wide range of liquid agents which are non-reactive with the acids under conditions of surfation (surface modification) add considerable dimension to the art.